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Numerical Models of 3-D Galactic Dynamos

Published online by Cambridge University Press:  19 July 2016

J.S. Panesar ,
N. Moore  and
A.H. Nelson
J.S. Panesar
Affiliation:
Physics Department, University of Wales College of Cardiff P.O. Box 913, Cardiff CF1 3TH, UK
N. Moore
Affiliation:
Physics Department, University of Wales College of Cardiff P.O. Box 913, Cardiff CF1 3TH, UK
A.H. Nelson
Affiliation:
Physics Department, University of Wales College of Cardiff P.O. Box 913, Cardiff CF1 3TH, UK

Abstract

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We describe here the results of 3-D numerical simulations of an αω-dynamo in galaxies with differential rotation, small scale turbulence, and a shock wave induced by a stellar density wave. A non-linear quenching mechanism for the dynamo instability is used, and with the model parameters employed the field achieves a steady state which closely resembles observed fields in galaxies. The magnetic field vectors are parallel to the plane in the disc, with the magnetic intensity decreasing away from the plane. The vectors are also nearly parallel to the spiral arms in the disc, and the field direction is axisymmetric about the galactic centre, but with significant increase of intensity in the arms. The magnetic intensity rises steeply towards the centre of the galaxy, where the field becomes dominated by the vertical component. Nowhere in the parameter range covered is the bi-symmetric field mode dominant.

Type
8. Magnetic Fields in Galaxies: Dynamo Theory
Information
Symposium - International Astronomical Union , Volume 157: The Cosmic Dynamo , 1993 , pp. 345 - 348
Copyright
Copyright © Kluwer 1993 

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